<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<script>
		var num=parseInt(prompt('请输入一个三位数的数字'))
		a=Math.floor(num/100);
		b=Math.floor(num%100/10);
		c=Math.floor((num%100)%10)
		
		console.log(c*100+b*10+a)
	</script>
</head>
<body>
	
</body>
</html>